The IgG/IgE blood test measures the levels of immunoglobulin G (IgG) and immunoglobulin E (IgE) antibodies in the blood. IgG and IgE are types of antibodies produced by the immune system in response to different antigens, such as allergens or pathogens. The test is used to assess allergic or immune responses in individuals who may be experiencing symptoms related to allergies or certain immune disorders.